Flue heat extractor



Feb. 16, 1943. J, GRQTENHQUSE I 2,311,226

FLUE HEAT EXTRAC'IOR Filed April 12, 1940 EN TOR.

ATTORN Patented Feb. 16, 1943 FLUE. HEAT EXTRACTOR James T. Grotenhouse, Orange City, Iowa, as-

signor to Silent Sioux Oil Burner Corporation, Orange City, Iowa, a corporation of Iowa Application April 12, 1940, Serial No. 329,356

2 Claims.

An object of my invention is to provide a flue heat extractor which will absorb or draw the heat from the flue and to provide this result in a compact arrangement.

A further and important object of my invention is to provide a device which extracts the heat from the flue and which also forces heated air thus formed outwardly into the space to be heated.

A further object of my invention is to provide an arrangement of lengthened passages which will efiiciently absorb the heat from the flue,

with certain positive draft arrangements at-.

tached thereto which will direct the heated air substantially at right angles to such passageways.

} A further object of my invention is to provide a flue heat extractor which is so devised-that it can be used in combination with a unit heater to increase the heat effect therefrom by adding the maximum portion of the flue heat thereto.

A furtherobject of my invention is to provide an arrangement of this character which can be attached to any type of flue, either at a distance from the heat unit or adjacently thereto.

A further object of my invention is to provide the above objects in a simple and compact structure.

With these and other objects in view, my invention consists in the construction, arrangement, and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 is a sectional view taken through the flue heat extractor and substantially along the lines II of Fig. 2,

Figure 2 is a sectional view taken substantially along the lines 2-2 of Fig. 1, and

Fig. 3 is a side elevation of the unit as used with a heater.

My invention contemplates principally the provision of an arrangement wherein the heat which is usually wasted in a chimney flue will be extracted from the flue, and will then, by means of a forced draft, be blown into the space which is to be heated. The provision of such a forced draft provides a maximum efliciency to such an arrangement in that the heat is forced into the desired spac in a positive manner without the necessity of relying entirely upon a natural draft circulation.

I have used the character ID to designate a flue connected to a suitable heater of any type,

and attached to the member ID is the further cylindrical member II which communicates at I2 with a hollow rectangular chamber I3 having the end walls I4 and I5 and the side walls I6 and IT. The chamber I3 also includes the top wall I8 which communicates at I9 with the further member 20 to which can be attached a further pipe 2 I Spaced a slight distance from the chamber I3 and receiving the same is the further outer casing 22 having the end walls 23 and 24 and the side Walls 25 and 26 which merge with the top wall 21 through which the member 23 passes. The walls 25 and 26 include the openings 28 at the upper ends thereof, and the outer casing extends downwardly to the lower end at 29 which end is open. An open grill 30 is provided in the forward wall 24 having the deflecting fins 3|.

Attached at the bottom of the walls I4, I5, I6, and I1 is the lower base member 32. The plate 32 also forms the base or bottom of a further inner lengthened chamber 33 having the end walls 34 and 35 and the side walls 36 and 31. Communicating at 38 with the forward wall 35 of the chamber 33 is the horizontal open tube 39 which communicates exteriorly of the casing. wall I5 at 40. The inner chamber 33 includes the top curved wall 4|. Attached at 42 and passing through the lower base 32 are a pair of pipes 43 which communicate with the blower housings 44 which housings 44 include the radially positioned blowing blades 45 and the outwardly facing openings 46. An electric motor 41 is suitably attached to the blades 45 to rotate the same. A pair of brackets 410. are suitably attached beneath the plate 32 to support the unit comprising the blowers and electric motor.

The operation of the arrangement is as follows. It will be understood from the previous description that the arrangement is attached at any point in a flue circuit from which it is desired to extract the heat, and the pipes I0 and 2I thereby form one of the means for such attachment, although other means can be employed. The electric motor is started, and usually this motor is a very small fractional horsepower motor requiring very little electricity to operate. The

flue heat and gases which pass out of the pipe I0 pass upwardly in the direction of the arrows 43 within the chamber I3 and around the inner chamber 33. These heated gases then pass upwardly and continue out of the pipe 2| where they are then exhausted. The blowers 44 take air in through the intake openings 46 in the direction of the arrows 49 and force this air upwardly in the direction of the arrows 50, which air currents are then deflected in the direction of the arrow 5| outwardly through the tube 39, thence through the opening 40 and through the grill structure 30 It will be noted that, as the current of air is forced upwardly, it will absorb heat from the walls 34, 35, 36 and 31, which heat is transferred to these walls by means of the rising flue gases. By means of the positive draft of air thus provided, this heat is drawn off quickly and at the highest possible efficiency, which would not be possible with a static condition or a condition of natural draft. The heat thus extracted then travels through the grill 3!) as explained, and passes outwardly through the deflecting fins 3i into the space to be heated. Meanwhile, through natural draft, air will be drawn upwardly in the direction of the arrows 52 between the outermost casing and the inner casing I3 in the smaller space provided, which air enters through the lower opening of the outer casing and rises to the side openings 28 and passes out through these openings to provide an additional heating effect. A portion of this heated air also rises through a suitable opening Ila, provided about the pipe H and also passes through the grill 3%.

It has been found that the device in operation reduces the flue temperature considerably, thereby indicating the extraction of a comparatively large amount of heat which can be utilized for the desired purposes, and which is thus positively forced in the desired direction for both reasons; viz., that of getting the greatest heat efliciency through a positive draft and that of directing the heat to the desired area.

Figure 3 illustrates a type of apparatus in which the heat extractor can be employed in which the character 53 designates a heater of the oil burner or other type having the upper grill 54 through which the ascending heated air rises in the direction of the arrows 55. The unit heretofore described is attached at the rear of the unit 53 as shown, and the heated air blowing across the top of the heater 53 from the grills 30 in the direction of the arrows 56 will merge with the rising air stream and force a considerably augmented current of heated air across the unit and into the room, thereby providing a combined result of additional efficiency. I

It will now be seen that I have provided a flue heat extractor having all of the advantages enumerated above in the objects of my invention, and it will be seen that I have provided other advantages readily apparent.

I claim as my invention:

1. A flue heat extractor comprising a heat extracting member attached to a flue for extracting heat therefrom, positive draft means attached thereto for forcing the heat thus extracted away from said heat extracting member, including blower members adapted to force air along the surface of said heat extractor member and outwardly therefrom, an inner hollow chamber communcating with said blowers, a hollow member surrounding and spaced from said inner chamber, means for passing flue gases exteriorly of said inner chamber and interiorly of said member to transfer heat from said flue gases to said inner chamber, an external casing spaced from said member, said external casing having an opening including a grill, said inner chamber having a passage communicating exteriorly of said member for the outlet of heated air, said grill being positioned adjacent to the outlet of said passage.

2. A flue heat extractor comprising a heat extracting member attached to a flue for extracting heat therefrom, positive draft means attached thereto for forcing the heat thus extracted away from said heat extracting member, including blower members adapted to force air along the surface of said heat extractor member and outwardly therefrom, an inner hollow chamber communicating with said blowers, a hollow member surrounding and spaced from said inner chamber, means for passing flue gases exteriorly of said inner chamber and interiorly of said member to transfer heat from said flue gases to said inner chamber, an external casing spaced from said member, said external casing having an opening including a grill, said inner chamber having a passage communicating exteriorly of said member for the outlet, of heated air, said grill being positioned adjacent to the outlet of said passage, said external casing being closed at the top thereof and open at the bottom thereof to provide means for natural draft circulation between said external casing and said hollow member.

JAMES T. GROTENHOUSE. 

